What causes a bone spur?

A bone spur is a tiny growth of bone on top of normal bone.  A bone spur is the body's response to some kind of trauma.  The trauma could be due to pressure, rubbing or stress that continues over a long period of time. The spur is usually smooth and can cause pain.  The pain is typically due to the growth pressing on the soft tissues of the body such as ligaments, tendons, and nerves.  The most common places for spurs are in the feet, shoulders, spine, knees, hands, and hips. 

I have suffered from a heel spur for many years.  When I was younger I did not wear the best shoes and this tended to irritate the spur.  This was because the spur was due to the tissues in the bottom of my foot straining.  With the proper heel support this would not have been a problem.  I now wear shoes with adequate arch support. The results of not having the arch support was inflammation and difficulty walking.